A power conversion apparatus such as an inverter, which generates an AC voltage from a DC power-source such as a battery, is so constituted as to include the following configuration components: A main circuit (: power module) so constituted as to include components such as switching elements, a driving circuit (: gate driver) for generating a signal for driving the switching elements, a smoothing capacitor, a control circuit (: motor controller) for generating an operation signal to be transmitted to the driving circuit, and the like.
This type of power conversion apparatus performs the transmission/reception of the signals by connecting the control circuit inside the apparatus and a plurality of external appliances and sensors to each other with the use of a control wiring. This type of power conversion apparatus, however, is accompanied by the following problem: Namely, noise current and voltage, which mix into the power conversion apparatus by propagating through the control wiring, give rise to the occurrence of malfunctions of the control circuit and sensor circuits inside the apparatus. Accordingly, it is requested to devise a circuit-based or structure-based ingenuity for reducing the noise current and voltage which mix into the apparatus.
In order to reduce the electromagnetic noises which mix into the in-apparatus control circuit and the like through the control wiring, there exists a method of inserting a loss component or noise filter (capacitor) into the connection portion of the control wiring and an in-apparatus board and the like.
For example, there has been known PATENT LITERATURE 1 (JP-A-7-307637), where the disclosure has been made as follows: “A print-wiring-board-use noise filter wherein a large number of penetration-type noise filters are provided on a long and narrow strip-like board with a constant spacing placed therebetween, each of the penetration-type noise filters being configured by connecting a reactance element to a conduction wire, the conduction wire being orthogonal to a predetermined board, and penetrating the board, one end of each conduction wire of each penetration-type noise filter being connected to each connection end of a plurality of print wirings provided on a print wiring board, the other end of each conduction wire of each penetration-type noise filter being connected to each connection end of a plurality of print wirings provided on the other print wiring board.”